Process and apparatus for thermal cracking of hydrocarbons

ABSTRACT

Apparatus is provided for thermal cracking of hydrocarbons, which comprises a reaction column A having a reactor attached thereto, and a regenerator B having a combustion and heating chamber attached thereto (see FIG. 1), wherein the reaction column has a large diameter in the upward portion thereof and smaller diameter in the downward portion thereof, the reactor, using a dilute fluidized layer, being connected with the top of the reaction column, and on the other hand the regenerator has a large diameter in the upward portion thereof and a smaller diameter in the downward portion thereof, the combustion and heating chamber, using a dilute fluidized layer, being connected with the top of the regenerator. Means are provided for connecting the upper part of the reaction column to the lowermost portion of the regenerator, and similar means are provided for connecting the upper part of the regenerator to the lowermost portion of the reaction column. A refractory material maintained under concentrated, floatable, fluidized conditions is caused to circulate between the regenerator and reaction column as heat carrier, and to come in contact with hydrocarbons introduced into the reaction column, wherein thermal cracking results in the production of lower hydrocarbons. Means are provided for the thermal isolation of the reactor and reaction column, and similarly for the combustion and heating chamber and the regenerator. Also provided are means for the introduction of raw material hydrocarbons, steam, air and heat carrier into the apparatus. The apparatus is utilized in the thermal cracking of heavy hydrocarbons, resulting in the production of hydrocarbons of C1, C2, C3 and C4 types, especially ethylene.

Kunii et al.

[451 Jan. 2, 1973 [54] PROCESS AND APPARATUS FOR THERMAL CRACKING OFHYDROCARBONS [75] Inventors: Daizo Kunli, Bunkyo-ku, Tokyo;

Taiseki Kunugl, Minato-ku, Tokyo,

both of Japan [73] Assignee: Toyo Soda Manufacturing Co., Ltd.,

Tokyo, Japan 221 Filed: 1-m.3,1sw0

211 Appl. No.: 86,574

Related U.S. Application Data [63] Continuation-impart of Ser. No.669,736, Sept. 22,

'1967,'abandoned.

Foreign Application Priority Data March 3, 1967 Japan ..42/1350l Nov.10, 1966 Japan.... ..41/73957 Novl 10, 1966 .lapana ..41/73958 [52] U.S.Cl. ..260/683 R, 23/288 S, 208/53, 208/54, 208/127, 208/163, 208/164[51] Int. Cl. ..C07c 3/30, B0lj 9/18 [58] Field of Search ..260/683;208/53, 54, 127, 163, 9 208/164; 23/288 S References Cited UNITED STATESPATENTS 2,439,811 4/1948 Jewell ..208/l63 2,871,183 1/1959 Smith etal.... .....260/683 2,731,508 1/1956 Jahnig et al... .....260/6832,422,501 6/1947 Roetheli ..260/683 3,414,504 12/1968 Oldweiler.....208/53 2,948,670 8/1960 Bray et a1. ..208/l27 2,690,990 10/1954Adams'et al... ..208/53 2,684,931 7/1954 Berg ..208/164 PrimaryExaminer- Delbert E. .Gantz Assistant Examiner-C. E. SpresserAtt0rney-Wenderoth, Lind & Ponack 57 7 ABSTRACT Apparatus is providedfor thermal cracking of hydrocarbons, which comprises a reaction columnA having a reactor attached thereto, and a regenerator B having acombustion and heating chamber attached thereto (see FIG. 1), whereinthe reaction column has a large diameter in the upward portion, thereofand smaller diameter in the downward portion thereof, the reactor, usinga dilute fluidized layer, being connected with the top of the reactioncolumn, and on the other hand the regenerator has a large diameter inthe upward portion thereof and a smaller diameter in the downwardportion thereof, the combustion and heating chamber, using a dilutefluidized layer, being connected with the top of the regenerator. Meansare provided for connecting the upper part of the reaction column to thelowermost portion of the regenerator, and similar means are provided forconnecting the upper part of the regenerator to the lowermost portion 7of the reaction column. A refractory material maintained underconcentrated, floatable, fluidized conditions is caused to circulatebetween the regenerator and reaction column as heat carrier, and to comein contact with hydrocarbons introduced into the reaction column,wherein thermal cracking results in the production of lowerhydrocarbons. Means are pro- The apparatus is utilized in the thermalcracking of heavy hydrocarbons, resulting in the production ofhydrocarbons of C C C and C types, especially ethylene.

5 Claims, 3 Drawing Figures PATENTEUJM 21w 3,708,552

' SHEEI 1 OF 2 27 V w m I 2 2a 8 7 4 A U 33 E 2 as-5 1-1] 1111/ [Ill/I7DAIZO KUNII and TAISEKI KUNUGI, Inventors Attorneys 1. PROCESS ANDAPPARATUS FOR THERMAL CRACKING OF HYDROCARBONS This application is acontinuation-in-part of Ser. No. 669,736, filed Sept. 22, 2967, nowabandoned.

The present invention relates to a process, and to an apparatus forpracticing such process, for obtaining mainly ethylene, which comprisesthe advantageous production of ethylene by thermal cracking of heavyhydrocarbons, wherein coke grains, sand grains and other refractorygrains having a somewhat large average grain size, e.g., about 0.2 to mmand optimally about 0.2 to 5 mm average grain size, are caused tocirculate as heat carrier between a reaction column and a regenerator,and hydrocarbons, particularly the heavy oil type of hydrocarbons,introduced into the reaction column, contact the heat carrier maintainedunder concentrated, floatable, fluidized conditions, whereby the thermalcracking results primarily in the production of ethylene.

Further, more particularly, the present invention relates to a processand appurtenant apparatus for thermally cracking hydrocarbons, which arecharacterized as hereinafter set forth. Namely, the present inventioncomprises a reaction column with a reactor attached thereto and aregenerator with a combustion and heating chamber attached thereto,wherein the reaction column has a large diameter in the upward portionthereof, a relatively smaller diameter in the downward portion thereofand then a reactor having an upwardly larger cross section, using adilute fluidized layer of heat-carrying particles, is connected with thetop of the reaction column, and on the other hand the regenera tor has alarge diameter in the upward portion thereof, a relatively smallerdiameter in the downward portion thereof, and a combustion and heatingchamber having an upwardly larger cross section, using a dilutefluidized layer of heat-carrying particles, is connected with the top ofthe regenerator, the upper portion of the reaction column beingconnected with the bottom of the regenerator by a conduit and the upperportion of the regenerator being connected with the bottom of thereaction column by another conduit. Granular heat carrier heated bycombustion in the regenerator is conveyed mainly by self-gravitationinto the bottom of the reaction column and the heat carrier isconveyedup-' wardly in the form of a concentrated fluidized layer by feedingsuperheated steam and part of the raw material hydrocarbons into thereaction column, a concentrated floatable fluidized layer ofheat-carrying particles being formed inthe reaction column, the rawmaterial hydrocarbons to be cracked being fed into the reaction columnwhere cracking is effected by the heat of. the heat carrier. The reactoris partially isolated from the reaction column by means of a constrictedconnecting part, and the heat of the thermally cracked gas blown up fromthe concentrated fluidized layer contained in the reaction zone of thereaction column (i.e., the

in the reactor and, simultaneously, the temperature of the total gasproducts is quickly reduced by this thermal cracking and the thermallycracked gas is cooled and fixed.

Thus, secondary thermal cracking is controlled and the over cracking ofunsaturated hydrocarbons produced in the reaction column is avoided soas to eliminate loss due to secondary reaction and, simultaneously, tarproduced is caused to adhere to the heatcarrying particles, resulting inan efficient operation. Then, the cracked products are passed through acyclone to remove fine heat-carrying particles therefrom, and are thenconveyed into a quenching tower for bringing them in contact withhydrocarbons such as light kerosene or gasoline and steam and are thenquickly quenched.

Granular heat carrier overflowing from the fluidized conditions in thereaction column is transferred into tion and steam and air are fed intoit from below. Then the granular heat carrier in the condition of aconcen-- trated fluidized layer is blown up to the upper part of theregenerator, and air and fuel, if necessary, are fed into theregenerator to maintain the granular heat carrier in the regenerator ina concentrated floatable fluidized condition, and thereby combustion ofattached carbon components occurs. Then, the heat carrier, heated andregenerated by the above heat of combustion, overflows, and as abovementioned, such heat carrier is transferred into the bottom of thereaction column mainly by self-gravitation.

Further, a combustion and heating chamber having a larger cross sectiontoward the upper part thereof is provided on top of the regenerator, andthe combustion in the combustion and heating chamber containing a dilutefluidized layer of heat-carrying particles is accelerated by air blownin and up from the exterior surrounding the connection between theregeneratorandcombustion and heating chamber, and the combustion andheating chamber is maintained at a higher temperature thanthetemperature in the regenerator.

Thus, combustible gas blown up into the combustion and heating chamberand fine powdery coke attached to the heat-carrying particles of thedilute fluidized layer, which are also blown up into the combustion andheating chamber from the regenerator, are efficiently burned, and thecombustion and heating chamber is thus efiectively heated. Then, bydropping the heat carrier into the regenerator, the heat generated inthe combustion and heating chamber is recovered in the regenerator.

The present invention relates to the serial equipment, for thermalcracking of hydrocarbons, of the fluidized layer of coarse graincirculation type as above-mentioned.

The principal object of the present invention is to provide a processand corresponding apparatus for the advantageous thermal cracking ofhydrocarbons, in which the intended thermally cracked gas is producedfrom hydrocarbon oil in high yield and good thermal efficiency by usingcoarse granular. media. Moreover, the operationcan be easily regulatedand the reaction column and regenerator can be designed ata low height,so that relatively small scale equipment can be used. Besides the above,tar attachment in the interior of the equipment can be prevented as muchas possible and abrasion inside the equipment can be lessened, these andother numerous advantages flowing from the present process.

A concentrated fluidized layer in the above-mentioned process means aheat carrier porosity of 0.55 up to 0.85 and a dilute fluidized layermeans a heat carrier porosity of 0.85 or more.

In practicing the present invention, the temperature for the reactioncolumn is preferably selected in the range of 700C to 900C and thetemperature at the outlet of the reactor is preferably in the range of500C to 700C.

In other words, the temperature inside the reactor is preferablyspecified in the range of 500C to 700C in order to control secondarythermal cracking of the thermally cracked gas produced in the reactioncolumn.

Surplus heat in the reactor is utilized for thermal cracking of gaseoushydrocarbon or distilled oil produced by distilling crude oil providedfor the cooling use in the connected portion between the reaction columnand the reactor, the amount of hydrocarbons fed for this cooling useadvantageously being in the range of to 30 percent by weight inproportion to the amount of hydrocarbon oil fed into the reactioncolumn. As above-mentioned, the cooling inside the reactor has theeffect of cooling and fixing the thermally cracked gas produced in thereaction column and additionally another effect of maintaining adhesionbetween the produced tar and heat carrier particles.

Further, the temperature of the regenerator is preferably maintained inthe range of about 900C to 1,050C and the temperature in the combustionand heating chamber containing the dilute fluidized layer is desirablykept at 150C higher than the above specified range in the regenerator. I

A combustible gas such as carbon monoxide blown into the combustion andheating chamber containing the dilute fluidized layer and fine powderycoke attached thereto are burned by the air blown into the connectedportion between the combustion and heating chamber and the regenerator.A portion of heat generated above is employed for heating the heatcarrier, andthe heated heat carrier is dropped into the regenerator,whereby one part of surplus heat generated in the combustion and heatingchamber containing the dilute fluidized layer is recovered in theregenerator.

Further, a waste heat boiler is fitted to the combustion and heatingchamber in the upper part thereof and, thus, its temperature can beregulated as specified, and simultaneously the surplus heat can berecovered, these being factors which are ad-vantageous in practicing theprocess of the present invention.

The methods of carrying out the present invention are described withreference to the attendant drawings in which:

FIG. 1 shows one example of a vertical section view of the apparatus,established according to the present invention.

(a) and (b) in FIG. 2 are, respectively, a vertical sectional view ofthe connecting part between the reactor and the reaction column, and across sectional view at line AA.

However, the drawings are intended to be solely illustrative of theapparatus of the present invention and are not meant to limit theinvention.

In the drawings, in FIG. 1, A is a reaction column and B is aregenerator. Reaction column A has a reaction zone 1 of relatively largediameter in the upward part of the reaction column, and a reactor 2 isconnected with the top of the reaction column A, the reactor having arelatively large cross section toward the upward part thereof and anarrower cross section toward the bottom. Inside the reaction column A,coarse granular heat carrier material forms a concentrated floatablefluidized layer.

In the lower part 3 of reaction column A, the coarse granular heatcarrier of high temperature from the regenerator B is conveyed, in thestate of concentrated fluidized layer, into the upper part of thereaction column A.

While the primary thermal cracking is carried out in the reaction columnA, gaseous hydrocarbons or distilled oils obtained by distilling crudeoils are fed through conduit 4 in the constricted connecting part at thetop of reaction column A into reactor 2, and the gaseous hydrocarbons ordistilled oils are thermally cracked in the reactor 2 by utilizing thehigh temperature heat of the thermally cracked gas blown up from thereaction column A and also of the heat carrier particles floating intothe reactor 2. In this way, the primary thermally cracked gas blown upinto the reactor 2 is prevented from undergoing a secondary thermalcracking.

While FIG. 1 shows a single constricted passageway between the reactioncolumn A and the reactor 2, the connecting part between reaction columnA and reactor 2 may be in the form of two or three, preferably three,conduits, whereby the cooling velocity for the thermally cracked gas fedfrom the reaction column A into the reactor 2 is accelerated so that thereactor can be advantageously designed at a low height.

The thermally cracked products discharged from the reactor 2 passthrough a cyclone separator 5 and a cooling and washing apparatus 6 andare then transferred into the next apparatus for treatment. Pulverizedgranules settled in the cyclone 5 pass through a pipe 7 and return intoconduit 1 1.

The granular heat carrier at high temperature in the condition of aconcentrated fluidized layer is conveyed upwardly from the lower part 3in the reaction column A, by the action of steam introduced at severalsteam inlet pipes 8, 9, 9" and 9" fitted on the bottom and lateral wallof lower part 3 of the reaction column.

Raw material hydrocarbon, if necessary, may be fed into the lower part 3from all or one of inlet pipes 9', 9" and 9" on the lateral wall.

Further, hydrocarbon inlet pipes proper, such as supply memebers 10' and10 are fitted in the lower portion of the reaction zone 1, the feedingmethod being optionally selected, e.g., a mixed gas of raw material andsteam may be blown downwardly and laterally into zone 1 e.g., throughinlet pipes 10' and 10'.

A flow regulating valve 12 and a steam inlet pipe 13 for regulatinggaseous flow are fitted on the passage 1 1, which is employed forconveying, by self-gravitation, the granular heat carrier overflowingfrom the upper part of the fluidized layer in reaction column A into thebottom of regenerator B. Further, the passage 11 need not necessarily beof the configuration shown.

The granular heat carrier conveyed into the lowermost part ofregenerator B is moved up through the lower part 16 of the regenerator,maintaining the condition of concentrated fluidized layer by means ofsteam introduced from feed pipes 14, and 15" and the said carrier isconveyed into the upper part 17 of the regenei'ator having a relativelyenlarged diameter.

In the upper part 17 of the regenerator, in operation, the granular heatcarrier is retained in the condition'of a concentrated floatablefluidized layer. In the lower vertical extension of upper part 17, pipes18 and 19 for feeding heated air are mounted, and if necessary a feedpipe for gaseous or liquid fuel 20 is also fitted thereon.

The particular dispositions of the several pipes may be appropriatelychanged, if desired.

In the upper part 17 of the regenerator, carbon particles attached tothe granular heatcarrier, and other fuels, are burned, and the granularheat carrier at high temperature overflows from the floatable fluidizedlayer and drops by self-gravitation through the passage 21 and isconveyed to the bottom of reaction column A. Along the passage 21 thereare fitted a flow regulating valve 22 and a steam feed pipe 23 forregulating gaseous flow. This passage 21 need not necessarily be astraight line.

Thus, heat carrier of coarse grain is forced to circulate between thereaction column A and the regenerator B. A feed pipe 25 of coarse grainheat carrier is fitted at the upward part of regenerator B and adischarge pipe 26 is fitted at the lower part of the regenerator 13.

Furthermore, a combustion and heating chamber 27 containing a dilutefluidized layer of heat-carrying particles and having a larger crosssection toward the upward part thereof is connected with the top of theregenerator B.

By feeding air through a supply pipe 29 from the exteriorof the'connecting part 28, combustible gas and pulverized. coke powder from thelower part are burned and, further, by heating the heat carrier in thecombustion and heating chamber and dropping it into the regenerator, theheat of the dilute fluidized layer in the combustion and heating chamberis recovered. in this case, the connected part is desirably constrictedas shown at 28 and, thereby, the combustion of pulverized coke powderand combustible gas can be accelerated by the feeding of air. This,after'combustible gas, such Thus, hydrogen, carbon monoxide and methanehave been completely burned, the resultant gases pass through cyclone30, waste heat boiler 31 and air preheater 32, and are discharged.

The part of the heat carrier separated in the cyclone passes through thepipe 33 and returns to the fluidized layer in regenerator B, whereas theremainder passes through the pipe 34 and is discharged out of thesystem.

A combustion chamber 35 connected with the lower end of regenerator B isemployed mainly for starting use.

For the starting operation, gaseous or liquid fuel is blown from supplyinlet 36 and air is blown in from inlet 37. The high temperature gasobtained by this combustion is introduced into the bottom of regeneratorB through the grate 24 and thereby the granular heat carrier is heated.

As above-mentioned, the present invention relates to a process andapparatus therefor, for the thermal cracking of hydrocarbons, in which agranular heat carrier is burned under the conditions of a concentratedfloatable fluidized layer in the upper part 17 of the regenerator and isheated to high temperature, and the granular heat carrier then descendsmainly by selfgravitation through the passage 21 into the bottom ofreaction column A and the heat carrier in the form of concentratedfluidized layer is transported upward by steam into the upper part 1 ofthe reaction column.

Further, raw material hydrocarbons are fed from the pipes 9, 9" and 10'and 10" in the reaction column and the hydrocarbons, in contact with thegranular heat carrier in the concentrated floatable condition, arethermally cracked in the upper part 1 of the reaction column.

The high temperature gas generated by this thermal cracking acts, inturn to thermally crack the gaseous hydrocarbons or distilled oils,obtained by distilling crude oils, which are supplied through the supplyconduit 4 into the reactor 2, and simultaneously the temperature of thegenerated gas itself is reduced.

Configurations of reaction column A and regenerator B need notnecessarily be those shown in the drawings. Any shape of reaction columnand regenerator which has a comparatively smaller diameter toward thedownward part thereof and an appropriately larger diameter toward theupward part to enable the formation of the concentrated floatablefluidized layer can be acceptably utilized.

Furthermore, pipes or plates can be installed inside the members A and Bto help effect homogeneous floating movement. Further, the connectionbetween the reactor 2 and the reaction column A need not necessarily bea single opening. A connection involving two or more openings is alsoacceptable.

Further, the connecting part between the com bustion and heating chamber27 and the regenerator need not necessarily be as shown in the drawing.

The present invention relates to a process and appurtenant apparatus forthermally cracking hydrocarbons in compliance with the aboveillustratedv method I in which the thermal cracking and the regenerationof granular heat carrier are carried out in separate towers,

so that the equipment can be easily regulated, and carbon producedsecondarily can be completely utilized, providing good thermalefficiency, and wherein the thermally cracked gas contains a minoramount of carbon dioxide and carbon monoxide gases, enablingpurification to becarried out easily and, furthermore, wherein coarse,larger grains (compared with the known thermal cracking process or theknown process utilizing a fluidized layer) can be employed.Consequently, the quantity of raw material treated is large inproportion to the volume of the equipment, and the granular particleshaving a large flow velocity are substantially free from the possibilityof colliding with the wall surfaces so that the abrasions of granularparticles and equipment can be kept at a minimum.

Furthermore, circulation of granular particles is carried out in asequence of floatable fluidized layer downward moving solids byself-gravitation-floatable fluidized layer, and the reaction can becarried out by moving the granular particles upwardly in the reactioncolumn, so that the complete equipment system can be constructed at alow height compared with the size of the apparatus utilized in theprior' known processes.

Following are exemplary embodiments of thermal cracking of crude oilaccording to the present invention.

EXAMPLE 1 An apparatus as illustrated in FIG. 1 was employed, thereactor and reaction column (combined), and regenerator and combustionand heating chamber (combined) each being 1,575 mm in total height, thereactor having a maximum inside diameter of 105.3 mm and a height of 350mm. The reaction column had an inside diameter of 105.3 mm in its upperportion and an inside diameter of 35.7 mm in its lower portion, with areverse conic shape constricted downwardly, the portion connecting thereactor and the reaction column having an inside diameter of 35.7 mm. Asheat carrier, coke powder ,of 0.2 mm to 0.4 mm in grain size was usedand as a raw material hydrocarbon oil, Duri crude oil (Conradson carboncontent: 8.3 percent) was fed at 900 grams/hour, and as a quenchinghydrocarbon, naphtha was fed at 100 grams/hour. The thermal cracking wascarried out at 810C and the regeneration was practiced at 860C.

Circulation speed of heat carrier 30 kilograms/hour Porosity of reactionzone 0.73 Contact time 0.4 sec. Gasification rate in proportion to totalweight of hydrocarbon: 63.7% Gas yields in proportion to total weight ofhydrocarbon: H 1.5% CO, 4.4% CO 2.9% CH 16.0% C,H,, 2.3% C 14 27.4% c n,0.1% C .,l-l 7.7% C. hydrocarbons (containing CJ-l C 11,; and C H asmain components) 1.2% C,H 0.2%

EXAMPLES 11 TO V Equipment similar to that of Example 1 was employed,with'various factors being changed, and the results were obtained aslisted below:

Example 11 111 IV V Crude Oil Seria Minas Kuwait Khatji Content ofConradson carbon in crude oil (per cent 0.19 2.8 5.9 6.8 by weight) 1Flow rate of crude oil (kg/hr) 1.19 0.986 1.09 1.01 Hydrocarbon for theLight Heavy Kero- Proquenching use Naphtha Naphtha sene pane Range ofboiling point for 40 to 100 to 180 to said hydrocarbon (C) 110 180 260Flow rate of said hydrocarbon (kg/hr) 0.05 0.11 0. 18 0.20 Flow rate ofsteam in reaction zone (kg/hr) 0.82 1.34 1.26 1.05 Heat carrier Sandrefractory Carbon material Coke grain Grain size of heat carrier 0.2 to0.2 to 0.3 to 0.35 to (mm) 0.4 0.5 0.8 0.84 Porosity of reaction zone0.73 0.76' 0.75 0.79 Temperature in upper reaction column (C) 720 760805 850 Temperature in upper regenerator (C) 805 820 837 890 Flow rateof grain circulation (kg/hr) 26.7 23.8 31.6 21.6 Gasification rate inproportion to total weight of 60.9 67.6 68.9 70.3 hydrocarbon (per cent)Gas yields in proportion to total weight of hydrocarbon (per cent) H,0.6 1.0 1.0 1.5 CO 0.1 0.4 1.2 3.2 CO, 0.1 0.4 1.4 4.3 CH. 8.0 10.4 13.816.0 0,11, 0.3 1.1 1-1, 19.0 26.0 27.8 28.0 C H, 2.8 2.0 2.2 1.8 C H,16.8 13.5 9.0 5.8 C H 1.0 0.8 0.7 0.7 C H 4.0 4.7 7.3 4.7 C 11 (3.11 8.58.4 4.2 3.2

Contact time (sec) 0.85 0.62 0.50 0.40

Having thus disclosed the invention, what is claimed 1. An apparatus forproducing olefins by the thermal cracking of hydrocarbons whichcomprises a reaction column for forming a fluidized state of granularheat carrier, having a reactor attached to the top thereof, and aregenerator for burning carbon particles adhering to the granular heatcarrier thereby heating the heat carrier to maintain the heat carrier ina fluidized state, by means of supplying air and optionally fuel to theregenerator, having a combustion and heating chamber attached to the topthereof, the reaction column having a downward portion thereof ofsmaller diameter than the diameter of the upward portion thereof forconveying the granular heat carrier upward in a fluidized layer state bymeans of supplying superheated steam and a portion of the raw materialhydrocarbon to the reaction column, thereactor being connected to thetop of the reaction column by means of a constricted connecting part,the reactor utilizing the heat of thermally cracked product gas having ahigh temperature by submitting gaseous hydrocarbons or distilled oilsobtained from crude oil fed into the connecting portion between thereaction column and the reactor to thermal cracking by a dilutefluidized layer and simultaneously therewith the temperature of thetotal gas products is quickly reduced by the thermal cracking so thatthe thermally cracked product gas is fixed and tar produced adheres tothe granular heat carrier, the regenerator having a downward portion ofsmaller diameter than the upward portion thereof for conveying thegranular heat carrier upwardly in a fluidized state by means of blowingsteam and air from the lower portion of the regenerator, the combustionand heating chamber being connected to the top of the regenerator bymeans of a constricted connecting part, the combustion and heatingchamber being utilized for burning combustible gas and powdery cokeattached to the granular heat carrier and simultaneously heating thegranular heat carrier by means of blowing air into the constrictedconnection, the upper portion of the reaction column being connected tothe bottom of the regenerator for transferring the granular heat carrieroverflowing from the fluidized conditions in the reaction column intothe bottom of the regenerator substantially by self-gravitation, and theupper portion of the regenerator being connected to the bottom of thereaction column for conveying the granular heat carrier regenerated byheat of combustion in the regenerator into the bottom of the reactioncolumnsubstantially .by self-gravitation, the constricted connectingpart between the reaction column and the reactor containing at least oneconduit, and being such that the diameter at the constricted connectingpart is less than the diameter of the upper portion of the reactioncolumn, the constricted connecting part between the upper portion of theregenerator and the combustion and heating chamber containing at leastone conduit, and being such that the diameter at said latter constrictedconnecting part is less than the diameter of the upper portion of theregenerator, the reaction column being fitted with pipes for feeding rawmaterial hydrocarbons and pipes for feeding steam, the regenerator beingfitted with pipes for feeding air and fuel and pipes for feeding steamrespectively, the constricted connecting part between the reactioncolumn and the reactor being fitted with pipes for supplying gaseoushydrocarbons or distilled oils obtained from crude oil, and theconstricted connecting part between the regenerator and the combustionand heating chamber being fitted with pipes for feeding air.

2. A method for producing olefins by the thermal cracking ofhydrocarbons, comprising transferring a granular heat carrier, at hightemperature, from a regenerator into a juxtaposed reaction column,maintaining the granular heat carrier, in the reaction column, in aconcentrated floatable fluidized layer state by feeding superheatedsteam thereinto, feeding the raw material hydrocarbon to be thermallycracked into the upper part of the fluidized layer in the reactioncolumn, feeding gaseous hydrocarbons or distilled oils into a reactorthrough a connecting part between the reactor and the top of thereaction column, to .be thermally cracked under dilute fluidized layerconditions by means of the high temperature of the thermally cracked gasblown up into the reactor from v the fluidized layer in the reactioncolumn and the heat carried by the fine heat carrier accompanying thegas, thus simultaneously cooling all of the thermally cracked'ga's andrecovering it with high efficiency by preventingthe secondary reactionof unsaturated hydrocarbon produced in the fluidized layer in thereaction column, transferring the granular heat carrier from thereaction column into the regenerator, maintaining the granular heatcarrier, in the regenerator, in a concentrated fluidized layer state,feeding air or fuel into the regenerator, burningthe granular heatcarrier in the upper part of the regenerator under concentratedfloatable fluidized layer conditions, feeding air into a combustion andheating chamber through a connecting part between the combustion andheating chamber and the top of the regenerator, to burn combustible gasand fine'powdery coke attached to the heat-carrying particles blown upinto the combustion and heating chamber under dilute fluidized layerconditions from the regenerator, dropping the coarse coke grainsproduced in the combustion and heating chamber into the regenerator tothereby recover the heat generated in the combustion and heatingchamber, and transferring the granular heat carrier regenerated andheated by said combustion into the reaction column.

3. A method according to claim 2, wherein the heat carrier is selectedfrom the group consisting of coke, sand and refractory particles havingan average grain size offrom 0.2 to 10 mm.

4. A method according to claim 2, wherein the heat carrier is cokehaving a grain size of from 0.2 to 5 mm.

5. A method according to claim 2, wherein the temperature in thereaction column is maintained within a range of about 700C to about900C, the temperature in the reactor is maintained within a range ofabout 500C to about 700C, the temperature in the regenerator ismaintained within a range of about 900C to about 1,050C, and thetemperature in the combustion and heating chamber is maintained within arange of about 1,0 C to about 1,20OC.

2. A method for producing olefins by the thermal cracking ofhydrocarbons, comprising transferring a granular heat carrier, at hightemperature, from a regenerator into a juxtaposed reaction column,maintaining the granular heat carrier, in the reaction column, in aconcentrated floatable fluidized layer state by feeding superheatedsteam thereinto, feeding the raw material hydrocarbon to be thermallycracked into the upper part of the fluidized layer in the reactioncolumn, feeding gaseous hydrocarbons or distilled oils into a reactorthrough a connecting part between the reactor and the top of thereaction column, to be thermally cracked under dilute fluidized layerconditions by means of the high temperature of the thermally cracked gasblown up into the reactor from the fluidized layer in the reactioncolumn and the heat carried by the fine heat carrier accompanying thegas, thus simultaneously cooling all of the thermally cracked gas andrecovering it with high efficiency by preventing the secondary reactionof unsaturated hydrocarbon produced in the fluidized layer in thereaction column, transferring the granular heat carrier from thereaction column into the regeneratoR, maintaining the granular heatcarrier, in the regenerator, in a concentrated fluidized layer state,feeding air or fuel into the regenerator, burning the granular heatcarrier in the upper part of the regenerator under concentratedfloatable fluidized layer conditions, feeding air into a combustion andheating chamber through a connecting part between the combustion andheating chamber and the top of the regenerator, to burn combustible gasand fine powdery coke attached to the heat-carrying particles blown upinto the combustion and heating chamber under dilute fluidized layerconditions from the regenerator, dropping the coarse coke grainsproduced in the combustion and heating chamber into the regenerator tothereby recover the heat generated in the combustion and heatingchamber, and transferring the granular heat carrier regenerated andheated by said combustion into the reaction column.
 3. A methodaccording to claim 2, wherein the heat carrier is selected from thegroup consisting of coke, sand and refractory particles having anaverage grain size of from 0.2 to 10 mm.
 4. A method according to claim2, wherein the heat carrier is coke having a grain size of from 0.2 to 5mm.
 5. A method according to claim 2, wherein the temperature in thereaction column is maintained within a range of about 700*C to about900*C, the temperature in the reactor is maintained within a range ofabout 500*C to about 700*C, the temperature in the regenerator ismaintained within a range of about 900*C to about 1,050*C, and thetemperature in the combustion and heating chamber is maintained within arange of about 1,050*C to about 1, 200*C.